US4396255A - Standard photographic lens system - Google Patents

Standard photographic lens system Download PDF

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Publication number
US4396255A
US4396255A US06/197,278 US19727880A US4396255A US 4396255 A US4396255 A US 4396255A US 19727880 A US19727880 A US 19727880A US 4396255 A US4396255 A US 4396255A
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sub
lens
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reference symbols
lens system
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Expired - Lifetime
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US06/197,278
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English (en)
Inventor
Toshihiro Imai
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Olympus Corp
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Olympus Optical Co Ltd
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Assigned to OLYMPUS OPTICAL CO., LTD. reassignment OLYMPUS OPTICAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: IMAI TOSHIHIRO
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
    • G02B9/60—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having five components only

Definitions

  • the present invention relates to a standard photographic lens system and, more particularly, to a standard photographic lens system for which the distance from the first surface of the lens system to the film surface is short, back focal length is long though the focal length thereof is comparatively short, and field angle is wider than those of known standard photographic lens system.
  • the field angle (2 ⁇ ) is about 46° to 47°.
  • the lens system is used as an interchangeable lens system for a single-lens reflex camera comprising a quick-return mirror, which is most popular among single-lens reflex cameras, it is indispensable that the lens system has a long back focal length.
  • the ratio of back focal length to the focal length is 0.8f or less.
  • a primary object of the present invention to provide a standard photographic lens system of such type that the lens elements constituting the cemented doublet of Gauss type lens system arranged in front of stop are separated from each other for which the distance from the first surface of the lens system to the film surface is short, i.e., about 1.6 times of focal length of the lens system, the back focal length is long, i.e., 0.9 times or more of focal length thereof, and the field angle is 55° or more, and is wider than those of known standard photographic lens systems.
  • the lens system according to the present invention has lens configuration as shown in FIG. 1, i.e., it comprises a first, second, third, fourth and fifth lens components, the first lens component being a positive meniscus lens arranged convex toward the object side, the second lens component being a negative meniscus lens arranged convex toward the object side, the third lens component being a positive meniscus lens arranged convex toward the object side, the fourth lens component consisting of a negative lens and positive lens which are cemented together or separated from each other, and the fifth lens component being a biconvex lens.
  • the lens system according to the present invention is arranged to satisfy the following conditions.
  • reference symbol L represents the distance from the first surface of the lens system to the film surface (when the distance to the object is ⁇ )
  • reference symbol f represents the focal length of the lens system as a whole
  • reference symbol f B represents the back focal length
  • reference symbol f 2 represents the focal length of the second lens component
  • reference symbol f 23 represents the total focal length of the second and third lens components
  • reference symbols r 3 , r 6 and r 7 respectively represent radii of curvature of the surface on the object side of the second lens component, surface on the image side of the third lens component and surface on the object side of the fourth lens component
  • reference symbol n 6 represents the refractive index of the fifth lens component.
  • Conditions (1) and (2) are established for the purpose of attaining the object of the lens system according to the present invention.
  • the condition (1) is established in order to arrange the lens system compactly. If L becomes larger than the upper limit of the conditon (1), the lens system cannot be made compact. If L becomes smaller than the lower limit of the condition (1), thicknesses of lenses should be made small and, consequently, it becomes difficult to actually manufacture the lenses.
  • the condition (2) relates to the back focal length. If f B becomes smaller than the lower limit of the condition (2), it becomes impossible to obtain the required back focal length. If f B becomes larger than the upper limit, it becomes difficult for this type of lens system to correct aberrations in well balanced state and to thereby obtain a lens system with favourable performance.
  • Conditions (3) and (4) are to define the second and third lens components which are the most characteristic of this of lens system. Lower limits of these conditions are required for the purpose of bringing the rear principal plane of the lens system as a whole toward the image side in order to make the back focal length long. If f 2 and/or f 23 become smaller than the lower limits of conditons (3) and/or (4), it becomes impossible to make the back focal length long enough. Upper limits of conditions (3) and (4) are required for preventing aggravation of aberrations, chiefly spherical aberration. If, therefore f 2 and/or f 23 become larger than the upper limits of conditions (3) and/or (4), spherical aberration, coma, etc. will be aggravated and the image quality will decrease.
  • the conditions (5), (6) and (7) are established in order to make the back focal length long, i.e., about 0.9f. Besides, these conditions are established also in order to arrange so that the surface r 3 on the object side of the second lens component and surfaces r 6 and r 7 of the third and fourth lens components which are facing each other become approximately concentric in respect to the stop located between the third and fourth lens components and to maintain symmetry of offaxial rays by fulfilling the conditions (5), (6) and (7) at the same time as the conditions (3) and (4). That is, the lower limit of condition (5), upper limit of conditon (6) and lower limit of condition (7) are established in order to make the back focal length long.
  • the lower limits of conditions (5) and (6) and upper limit of condition (7) are required in order to minimize spherical aberration.
  • the upper limits of conditions (5) and (6) and lower limit of condition (7) are established in order to maintain symmetry of offaxial rays. Therefore, if r 3 becomes smaller than the lower limit of condition (5) and r 6 becomes larger than the upper limit of condition (6) and r 7 becomes smaller than the lower limit of condition (7), it becomes impossible to make the back focal length long and, moreover, spherical aberration becomes large. Spherical aberration becomes large also when r 3 becomes smaller than the lower limit of condition (5), r 6 becomes smaller than the lower limit of condition (6) and r 7 becomes larger than the upper limit of condition (7). It becomes impossible to maintain symmetry of offaxial rays if r 3 becomes larger than the upper limit of condition (5), r 6 becomes larger than the upper limit of condition (6) and r 7 becomes smaller than the lower limit of condition (7).
  • the upper limit of condition (8) is established in order to correct spherical aberration, which is overcorrected because radii of curvature r 10 and r 11 of respective surfaces of the fifth lens component are made large for the purpose of making the back focal length long.
  • powers of negative lenses become strong and, consequently, Petzval's sum becomes unfavourable.
  • the lower limit of condition (8) is established in order to correct Petzval's sum. If n 6 becomes larger than the upper limit of condition (8), spherical aberration will be overcorrected. If n 6 becomes smaller than the lower limit of condition (8), Petzval's sum becomes unfavourable.
  • the fourth lens component of the lens system according to the present invention may be arranged either as a cemented doublet or as two separate lens elements having a small airspace between them.
  • influence on aberrations etc. becomes slightly different from the case that the fourth lens component is arranged as two separate lens elements. Taking this point into consideration, it is preferable to attach different conditions shown below to the cases that the fourth lens component is arranged as a cemented doublet and as a two separate lens elements.
  • the fourth lens component When the fourth lens component is arranged as a cemented doublet, it is necessary to make the negative refractive power of cemented surface strong in order to make the back focal length long.
  • f 23 in the condition (4) is selected in the range of -1.2f ⁇ f 23 ⁇ -1.07f.
  • the fourth lens component is arranged as two separate lens elements, it is possible to make the back focal length satisfactorily long when n 4 and n 5 are arranged as 0.03 ⁇ n 4 -n 5 so that the air lens formed between the negative and positive lens elements constituting the fourth lens component has negative refractive power and, moreover, when d 4 and f 23 are selected as 0.03f ⁇ d 4 and f 23 ⁇ -2.8f.
  • the fourth lens component is arranged as two separate lens elements, it is more preferable to select f 23 in the condition (4) as -3f ⁇ f 23 ⁇ -2.8f.
  • the focal length f A of air lens which is formed between the negative and positive lens elements of the fourth lens component due to the fact that they are arranged as separate lens elements, is selected as -10f ⁇ f A .
  • the focal length f A is expressed by the following formula wherein reference symbol d 7 ' represents the thickness of air lens, and reference symbols r 8 and r 8 ' respectively represent radii of curvature of respective surfaces of air lens. ##EQU1## It is possible to make the back focal length f B satisfactorily long when it is arranged as -10f ⁇ f A , 0.03 ⁇ n 4 ⁇ n 5 , 0.03f ⁇ d 4 , and -3f ⁇ f 23 ⁇ -2.8f as described in the above. If any of these conditions are not satisfied, it becomes difficult to make f B satisfactorily long.
  • FIG. 1 shows a sectional view of Embodiments 1 and 2 of the lens system according to the present invention
  • FIG. 2 shows a sectional view of Embodiments 3 and 4 of the lens system according to the present invention.
  • FIGS. 3 through 6 respectively show graphs illustrating aberration curves of Embodiments 1 through 4 of the present invention.
  • reference symbols r 1 through r 11 respectively represent radii of curvature of respective lens surfaces
  • reference symbols d 1 through d 10 respectively represent thicknesses of respective lenses and airspaces between respective lenses
  • reference symbols n 1 through n 6 respectively represent refractive indices of respective lenses
  • reference symbols ⁇ 1 through ⁇ 6 respectively represent Abbe's numbers of respective lenses.
  • Embodiments 1 and 2 have lens configuration shown in FIG. 1 and their fourth lens components respectively consist of two lens elements, i.e., the negative and positive lens elements, which are separated from each other.
  • Embodiments 3 and 4 have lens configuration shown in FIG. 2 and their fourth lens components are arranged as cemented doublets.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)
US06/197,278 1979-10-18 1980-10-15 Standard photographic lens system Expired - Lifetime US4396255A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP54-134623 1979-10-18
JP13462379A JPS5659216A (en) 1979-10-18 1979-10-18 Standard lens with wide angle of view

Publications (1)

Publication Number Publication Date
US4396255A true US4396255A (en) 1983-08-02

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US06/197,278 Expired - Lifetime US4396255A (en) 1979-10-18 1980-10-15 Standard photographic lens system

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US (1) US4396255A (enrdf_load_stackoverflow)
JP (1) JPS5659216A (enrdf_load_stackoverflow)
DE (1) DE3039507A1 (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1302802A3 (de) * 2001-10-09 2004-03-03 Siemens Aktiengesellschaft Kameramodul für ein Mobilfunkgerät
US20060061881A1 (en) * 2004-09-23 2006-03-23 Asia Optical Co., Inc. Compact lens system
US20060221467A1 (en) * 2005-04-01 2006-10-05 Asia Optical Co., Inc. Compact lens system
US20190146193A1 (en) * 2016-05-13 2019-05-16 Kantatsu Co., Ltd. Imaging lens
CN110618517A (zh) * 2018-06-20 2019-12-27 大立光电股份有限公司 摄影用光学镜头、取像装置及电子装置

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3907928C2 (de) * 1989-03-11 1997-11-06 Rodenstock Optik G Objektiv für Großformat-Kameras
JP4824981B2 (ja) * 2005-09-21 2011-11-30 オリンパスイメージング株式会社 結像光学系及びそれを備えた交換レンズ装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4214815A (en) * 1977-06-23 1980-07-29 Konishiroku Photo Industry Co., Ltd. Semi-wide angle objective lens

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2252975A1 (de) * 1972-10-28 1974-05-02 Helmut Gimmler Vorfabriziertes bauelement zur herstellung von heizkoerpernischen

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4214815A (en) * 1977-06-23 1980-07-29 Konishiroku Photo Industry Co., Ltd. Semi-wide angle objective lens

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1302802A3 (de) * 2001-10-09 2004-03-03 Siemens Aktiengesellschaft Kameramodul für ein Mobilfunkgerät
US20060061881A1 (en) * 2004-09-23 2006-03-23 Asia Optical Co., Inc. Compact lens system
US7236314B2 (en) 2004-09-23 2007-06-26 Asia Optical Co., Inc. Compact lens system
US20060221467A1 (en) * 2005-04-01 2006-10-05 Asia Optical Co., Inc. Compact lens system
US7236315B2 (en) 2005-04-01 2007-06-26 Asia Optical Co., Inc. Compact lens system
US20190146193A1 (en) * 2016-05-13 2019-05-16 Kantatsu Co., Ltd. Imaging lens
US10795133B2 (en) * 2016-05-13 2020-10-06 Kantatsu Co., Ltd. Imaging lens
CN110618517A (zh) * 2018-06-20 2019-12-27 大立光电股份有限公司 摄影用光学镜头、取像装置及电子装置
CN110618517B (zh) * 2018-06-20 2021-08-31 大立光电股份有限公司 摄影用光学镜头、取像装置及电子装置

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Publication number Publication date
JPS5659216A (en) 1981-05-22
DE3039507A1 (de) 1981-04-30
JPH0119125B2 (enrdf_load_stackoverflow) 1989-04-10

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